Contact Lens Case Reports
Water Intake and Dry Eye
By Patrick J. Caroline, FAAO, & Mark P. André, FAAO
Clinical experience has taught us that topical tear supplements for dry eye management often provide only temporary relief of the symptoms. Today, a growing number agree that in many dry eye patients, long-term management is best accomplished through systemic treatments and changes in dietary intake.
For years practitioners have suggested that increasing daily water intake may benefit dry eye patients, but in reviewing the scientific literature we were unable to find any published studies that support this theory. In an attempt to bring some clarity to this question, our research team at Pacific University performed the following pilot study.
Materials and Methods
For purposes of this pilot study, our recruitment population consisted solely of Pacific University Campus students and faculty who all gave consent to participate. The 29 subjects were identified as normal or as having dry eye through their subjective responses to the Texas Eye Research and Technology Center Dry Eye Questionnaire, which we selected because it had been previously validated and was noted to have a 75-percent sensitivity and 100-percent specificity in diagnosing dry eye. A questionnaire score above 32 indicates dry eye.
After completing the questionnaire, 12 subjects were identified as normal and 17 as having dry eye. We then asked each participant to drink a specified amount of water each day for 14 days and to record their actual intake in ounces. The amount of water for each participant was determined by entering the subject's weight and gender into the National Institute of Medicine's suggested water intake calculator. Figure 1 shows the amount of water intake for each subject, with the average being 80 ounces a day. Each subject was asked to change nothing else in their daily systemic or topical routine.
Figure 1. The amount of water intake per subject, average 80 ounces.
One subject (#16) voluntarily dropped out of the study, stating that the increased water intake made him nauseous. With the remaining 28 subjects, a two-sample paired t-test was performed to compare the pre- and post-water treatment questionnaire scores. Both groups showed a statically significant reduction in the questionnaire score at a level of P<0.05. However, individuals who started out as normal had a statical significance of P=0.0356, while individuals in the dry eye group had a statical significance of P=0.000109 (Figure 2).
Figure 2. Subjective dry eye questionnaire results pre- and post-water intake.
The results of this pilot study appear to indicate that an increase in daily water intake does indeed decrease the symptoms of dry eye in some subjects. In this study, of the 17 subjects who had pre-treatment dry eye, 13 went into the “normal” group after two weeks of increased water intake.
It is important to reiterate that this was only a pilot study and that the results need to be scientifically validated through more extensive objective protocols and increased subject numbers. CLS
Patrick Caroline is an associate professor of optometry at Pacific University. He is also a consultant to Paragon Vision Sciences. Mark André is an associate professor of optometry at Pacific University. He is also a consultant for CooperVision.